Topic: Requests. Aggregate functions. The help is very necessary
Hello! I suffer already some time, with three requests. It is impossible anything, too difficult for me. Help to implement them, please!!!
Drugstores in which there are medicines, no given vendor;
Steams of vendors which do not have any identical medicine;
Drugstores in which there are all medicines.
P.S. In .rar everything that is necessary for performance: the chart /, the filled tables and a file in a format bak.